A circuit arrangement of this kind is known from EP 0 162 341. Switching off when reaching a certain accumulator voltage is carried out there by means of a rocker stage formed from the second and third transistors. As soon as the set ideal voltage is reached the first transistor which is designed as a switch transistor is blocked and is released again immediately the ideal voltage is understepped. With this known circuit arrangement after the start of charging the charging current decreases comparatively rapidly with an empty accumulator (cf FIG. 3).
From EP 0 383 383 A1 there is known an electronic switch. network part for supplying current to an accumulator with parallel-connectable direct current motor from an alternating or direct current source with a primary beat blocking converter which contains a transmitter whose primary winding is connected in series with a first transistor and a first resistance. The secondary winding of the transmitter lies in series with a diode and the accumulator and is connected to the base of the first transistor by the series connection of a second resistance and a capacitor. A circuit is provided to change from rapid charging to constant charging on reaching a predetermined accumulator voltage and to feed the direct current motor with constant voltage independent of the charge. This circuit contains a voltage divider connected to the emitter of the first transistor and having two series connected resistances and a second transistor whose base is attached to the connection of the second resistance with the capacitor.